The human shoulder is a highly mobile structure whose function is to position the hand almost anywhere within a nearly spherical range of motion. Many features of this complex region in humans, including the function of certain muscles, are shared with the living apes, as was previously demonstrated by this investigator and others using electromyographic studies. The present proposal describes a new set of functionally interpretable osteological features of the scapula and humerus that have been suggested by the results of previous electromyographic studies of shoulder muscle function among living apes and humans. It follows in the tradition of S.L. Washburn who more than three decades ago urged the use of experimental comparative anatomy to help answer questions of human inheritance. Analysis of a new set of features in the skeleton of the shoulder will further our understanding of the relationship between form and function, as well as expand the collection of functional characters that may be applied to the interpretation of human fossils. This will aid in our understanding of this region of the body.
